Production of Piston Pin Having a New Helical Inner Profile by Cold Metal Forming

The improvement of powertrain and chassis components concerning lightweight design has drawn significant attention and interest in recent years in the automotive lightweight industry. The Lightweight Forging Initiative “Lightweight Forging”, funded by AiF (the German Federation of Industrial Research Associations) and BMWi (The Federal Ministry for Economic Affairs and Energy) was established to highlight the contributions from the forging industry to the automotive megatrend of lightweight design and to make it accessible to the professional world. As a part of the project “Lightweight Forging” Research Network, a new helical internal geometry of piston pins that offers the possibility of combining stiffness and lightweight design into one component has been developed. This paper focuses on the numerical determination of factors influencing the form-filling behaviour of inner helix shape and the process limits by manufacturing of piston pins with trapezoidal cross section of a helix shaped internal profile by ironing. In order to determine these dependencies, the tribological conditions between forged part and tool as well as parameters of the mandrel outer profile were varied.